Qianqian Ding

Zincobyric acid and zincobalamin, the Zn‐analogues of cobyric acid and of vitamin B₁₂, were efficiently prepared from the metal‐free corrin, hydrogenobyric acid. The crystal structure of the zincobyrate, the first of a Zn‐corrin, revealed a significant misfit of the closed shell Zn^II‐ion to the corrin ligand. The luminescent Zn‐mimics of vitamin B₁₂ do not support organometallic B₁₂‐enzyme reactions and may be useful enzyme inhibitors.

Abstract

Replacing the central cobalt ion of vitamin B₁₂ by other metals has been a long‐held aspiration within the B₁₂‐field. Herein, we describe the synthesis from hydrogenobyric acid of zincobyric acid (Znby) and zincobalamin (Znbl), the Zn‐analogues of the natural cobalt‐corrins cobyric acid and vitamin B₁₂, respectively. The solution structures of Znby and Znbl were studied by NMR‐spectroscopy. Single crystals of Znby were produced, providing the first X‐ray crystallographic structure of a zinc corrin. The structures of Znby and of computationally generated Znbl were found to resemble the corresponding Co^II‐corrins, making such Zn‐corrins potentially useful for investigations of B₁₂‐dependent processes. The singlet excited state of Znby had a short life‐time, limited by rapid intersystem crossing to the triplet state. Znby allowed the unprecedented observation of a corrin triplet (E ^T=190 kJ mol⁻¹) and was found to be an excellent photo‐sensitizer for ¹O₂ (Φ_Δ=0.70).

A novel single‐step and chemical‐free process for the fabrication of broadband, omnidirectional, antireflective glass, using laser nanostructuring, is demonstrated. Nanostructures are selectively textured on glass to mimic the morphology and the remarkable antireflection properties found on the Greta oto butterfly and Cicada wings. Bioinspired glass could revolutionize the antireflection technology and impact numerous applications, ranging from displays to optoelectronic devices.

Abstract

Here, a single‐step, biomimetic approach for the realization of omnidirectional transparent antireflective glass is reported. In particular, it is shown that circularly polarized ultrashort laser pulses produce self‐organized nanopillar structures on fused silica (SiO₂). The laser‐induced nanostructures are selectively textured on the glass surface in order to mimic the spatial randomness, pillar‐like morphology, as well as the remarkable antireflection properties found on the wings of the glasswing butterfly, Greta oto, and various Cicada species. The artificial structures exhibit impressive antireflective properties, both in the visible and infrared frequency ranges, which are remarkably stable over time. Accordingly, the laser‐processed glass surfaces show reflectivity smaller than 1% for various angles of incidence in the visible spectrum for s–p linearly polarized configurations. However, in the near‐infrared spectrum, the laser‐textured glass shows higher transmittance compared to the pristine. It is envisaged that the current results will revolutionize the technology of antireflective transparent surfaces and impact numerous applications from glass displays to optoelectronic devices.

Responsive optical nanomaterials have attracted long‐standing research interests owing to their promise in both fundamental studies and practical applications. The current research activities on responsive optical nanomaterials are reviewed, with special focus on optical diffraction, absorption, refraction, and emission. Perspectives are also provided to point out the possible directions for future research.

Abstract

Responsive optical nanomaterials that can sense and translate various external stimuli into optical signals, in the forms of observable changes in appearance and variations in spectral line shapes, are among the most active research topics in nanooptics. They are intensively exploited within the regimes of the four classic optical phenomena—diffraction in photonic crystals, absorption of plasmonic nanostructures, as well as color‐switching systems, refraction of assembled birefringent nanostructures, and emission of photoluminescent nanomaterials and molecules. Herein, a comprehensive review of these research activities regarding the fundamental principles and practical strategies is provided. Starting with an overview of their substantial developments during the latest three decades, each subtopic discussion is led with fundamental theories that delineate the correlation between nanostructures and optical properties and the delicate research strategies are elaborated with specific attention focused on working principles and optical performances. The unique advantages and inherent limitations of each responsive optical nanoscale platform are summarized, accompanied by empirical criteria that should be met and perspectives on research opportunities where the developments of next‐generation responsive optical nanomaterials might be directed.

In article number 1803730, Bettina V. Lotsch and co‐workers develop an all‐optical method to track analyte uptake and diffusion by a 2D nanosheet‐based photonic multilayer system. Molecular diffusion of amines is monitored by a combination of optical spectroscopy and theoretical modelling, thus allowing the spatially resolved tracking of molecular diffusion in real time, based on a simple optical read‐out.